This invention covers a Constant-Velocity Joint in tripod construction having an external joint component in which, circumferentially spaced, three axial guide tracks are formed with bearing surfaces opposite each other in the circumferential direction; an interior joint component having three circumferentially spaced radial trunnions formed to engage in the guide tracks; and with one roller unit on each of the trunnions, radially supported in the guide tracks in which they are essentially held at constant angles, and which are--relative to the trunnions--radially movable with angular mobility, while the roller units are each mounted, free the rotate, on a roller carrier, and the trunnions have each permanently connected to their ends, spherical heads which engage in a radial internal recess of a roller carrier, radially sliding and with angular mobility.
Plain tripod-type joints whose roller units run coaxially with their respective trunnions, are burdened with the disadvantage that in a bent joint the oscillating axial movements of the rollers within their tracks do not represent a pure rolling motion but, due to the angular position of the rollers relative to the direction of motion, also include a sliding component. This tends to generate substantial frictional forces which will initiate axial vibrations propagating from the joint. Comparatively speaking, it is an improvement to have in a bent joint the roller units oscillate in their guide tracks at correct angles and with pure rolling motion while the sliding motions, i.e., (1) the radial shifting of the roller units on their trunnions, and (2) the angular motion of the roller units relative to the trunnion, occur on surface pairs independent of the guide tracks.
From DE 31 03 172 C 2, a joint of the referenced type has been known in which an interfacing ring with a spherical segment surface is allowed to slide radially along the cylindrical trunnion which in turn engages in the ball socket surface of a roller carrier. On the roller carrier, the roller unit runs on needles. The manufacturing process for this is rather complex, requiring two sets of interfacing, sliding surfaces--one of which being a ball/socket combination--to be machined.
From DE 28 31 044 A1, another tripod-type joint with a spherical trunnion has been known on which a needle bearing roller unit is directly swivel-mounted, while the individual bearing needles are retained directly in the roller unit, and directly contact the spherical trunnion. Here, the type of contact which is subjected to rather high unit loads, results in the early destruction of the bearing needles; furthermore, these unguided bearing needles which are axially secured to the roller unit in a conventional fashion, can misalign versus the roller axis, leading to malfunctions.
From DE 37 16 962 A1, a joint has been known in which an interface ring is mounted on the cylindrical trunnion, rotating on rolling elements, having a spherical outer surface which is guided in a cylindrical inner surface of the roller unit, with angular mobility and freedom to shift radially. Essentially, there is no relative rotational movement between the interface ring and the roller unit. The manufacture of this design is also rather complex, since the interface ring requires machining of a precise spherical sliding surface and also, on the roller unit, a precisely machined outer bearing surface must be produced.
From the older G 89 15 669.2, a joint of the initially cited type has been known in which the bearing needles of a needle bearing are designed to run on the cylindrical surfaces of the roller carrier (outside) and the roller unit (inside), and where roller carrier and rollers are axially, directly secured to each other in conventional ways, by means of a radial collar and retainer rings. Here also, the risk of cocking of the bearing needles relative to the axes, remains unchanged. The mutual axial retention of roller carrier and roller unit is, due to the number of parts required, rather complex in manufacture and complicated to assemble.